// Copyright tang.  All rights reserved.
// https://gitee.com/inrgihc/dbswitch
//
// Use of this source code is governed by a BSD-style license
//
// Author: tang (inrgihc@126.com)
// Date : 2020/1/2
// Location: beijing , china
/////////////////////////////////////////////////////////////
package com.gitee.dbswitch.sql.ddl.sql.impl;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import com.gitee.dbswitch.sql.ddl.AbstractDatabaseDialect;
import com.gitee.dbswitch.sql.ddl.pojo.ColumnDefinition;
import com.gitee.dbswitch.sql.ddl.type.PostgresDataTypeEnum;

/**
 * PostgreSQL方言实现类
 * 
 * @author tang
 *
 */
public class PostgresDialectImpl extends AbstractDatabaseDialect {

	private static List<PostgresDataTypeEnum> integerTypes;

	static {
		integerTypes = new ArrayList<>();
		integerTypes.add(PostgresDataTypeEnum.SERIAL2);
		integerTypes.add(PostgresDataTypeEnum.SERIAL4);
		integerTypes.add(PostgresDataTypeEnum.SERIAL8);
		integerTypes.add(PostgresDataTypeEnum.SMALLSERIAL);
		integerTypes.add(PostgresDataTypeEnum.SERIAL);
		integerTypes.add(PostgresDataTypeEnum.BIGSERIAL);
	}
	
	@Override
	public String getFieldTypeName(ColumnDefinition column) {
		int length = column.getLengthOrPrecision();
		int scale = column.getScale();
		
		StringBuilder sb = new StringBuilder();
		PostgresDataTypeEnum type = null;
		try {
			type = PostgresDataTypeEnum.valueOf(column.getColumnType().toUpperCase());
		} catch (IllegalArgumentException e) {
			throw new RuntimeException(String.format("Invalid PostgreSQL data type: %s", column.getColumnType()));
		}
		
		if(column.isAutoIncrement()) {
			if(!PostgresDialectImpl.integerTypes.contains(type)) {
				throw new RuntimeException(String.format("Invalid PostgreSQL auto increment data type: %s", column.getColumnType()));
			}
		}

		sb.append(type.name());
		switch (type) {
		case NUMERIC:
		case DECIMAL:
			if (Objects.isNull(length) || length < 0) {
				throw new RuntimeException(
						String.format("Invalid PostgreSQL data type length: %s(%d)", column.getColumnType(), length));
			}
			
			if (Objects.isNull(scale) || scale < 0) {
				throw new RuntimeException(
						String.format("Invalid PostgreSQL data type scale: %s(%d,%d)", column.getColumnType(), length, scale));
			}
			
			sb.append(String.format("(%d,%d)", length,scale));
			break;
		case CHAR:
		case VARCHAR:
			if (Objects.isNull(length) || length < 0) {
				throw new RuntimeException(
						String.format("Invalid PostgreSQL data type length: %s(%d)", column.getColumnType(), length));
			}
			sb.append(String.format(" (%d) ", length));
			break;
		case TIMESTAMP:
			if (Objects.isNull(length) || length < 0) {
				sb.append(" (0) ");
			} else if (0 == length || 6 == length) {
				sb.append(String.format(" (%d) ", length));
			} else {
				throw new RuntimeException(
						String.format("Invalid PostgreSQL data type length: %s(%d)", column.getColumnType(), length));
			}
			break;
		case DOUBLE:
			sb.append(" PRECISION ");
			break;
		default:
			break;
		}

		return sb.toString();
	}
	
	@Override
	public String getFieldDefination(ColumnDefinition column) {
		String fieldname = column.getColumnName();
		boolean nullable = column.isNullable();
		String defaultValue = column.getDefaultValue();
		//String comment=column.getColumnComment();

		StringBuilder sb = new StringBuilder();
		sb.append(String.format("\"%s\" ",fieldname.trim()));
		sb.append(this.getFieldTypeName(column));

		if (column.isAutoIncrement()) {
			//PostgreSQL/Greenplum数据库里可以有多个自增列
			sb.append(" ");
		} else {
			if (nullable) {
				sb.append(" DEFAULT NULL");
			} else if (Objects.nonNull(defaultValue) && !defaultValue.isEmpty()) {
				if (defaultValue.equalsIgnoreCase("NULL")) {
					sb.append(" DEFAULT NULL");
				} else if ("now()".equalsIgnoreCase(defaultValue)) {
					sb.append(" DEFAULT now() ");
				} else {
					sb.append(String.format(" DEFAULT '%s'", defaultValue));
				}
			} else {
				sb.append(" NOT NULL");
			}
		}
		
		return sb.toString();
	}

}
